Electrical apparatus



W. O. DWYER.

ELECTRICAL APPARATUS.

APPLICATION FILED NOV. 17. 1920.

1,386,849. Patented Aug. 9, 1921.

His Attorney.

UNITED STATES PATENT OFFICE.

WILLIAM O. DWYER, OI PITTSFIELD, MASSACHUSETTS, ASSIGNOR TO GENERL ELECTRIC COMPANY, A QORPORATION OF NEW YORK.-

ELECTRICAL APPARATUS.

Specification of Letters Patent.

Patented Aug. 9, 1921.

Application filed November 17, 1920. Serial No. 424,779.

.To all whom it may concern.-

Be it known that I, WILLIAM O. DWYER, a subject of the King of Great Britain, residing at Pittsfield, in the county ofBerkshire, State of Massachusetts, have invented certain new and useful Improvements in Electrical Apparatus, of which the following is a specification.

My invention relates to electrical apparatus, such as transformers, some reactances and the like and has for its object an improved arrangement of parts which is economical, eiiicient and readily manufactured.

More specifically my invention relates to an improved arrangement of insulating barriers about windings particularly designed for high voltage service whereby the dielectric hysteresis losses are reduced substantially to a minimum.

In the construction of electrical apparatus for high voltage service, 100,000 volts for instance, it is necessary that all the windings and current carrying parts shall be adequately spaced and insulated from parts at ground potential. This is particularly true for transformers which are designed for such service where the magnetic core which necessarily passes adjacent the windings at certain points is at ground potential.

It has become the practice in transformer design to introduce insulating barriers between the core and the windings inorder that the effective dielectric strength may be had without resort to clearances of commercially impractical dimensions. The use of solid insulating barriers in such arrangements has been found to be undesirable since at these high voltages the dielectric hysteresis losses do become appreciable and result in interior heating of the dielectric 'material and hence their aging and ultimate failure within a certain length of time.

In the practice of my invention I have provided insulating barriers between cores and high voltage windings which are ventilated in a novel manner, and hence are not subject to the deleterious action of the heat engendered by dielectric hysteresis or other causes.

For a more complete understanding of the nature and object of m invention reference should be had to the ollowing detailed description in connection with the accompanying drawing in which:

Figure 1 is a v1ew mamly 1n perspectlve showing an insulating barrier embodying my invention, while Fig. 2 is a view in side elevation, parts being broken away, showmg a transformer provided with barriers (tzonstructedin accordance with my invenion.

Referring now to the drawing, 10 denotes an outer channel-shaped insulating member, and 11 an inner channel-shaped insulatlng member, which members are secured together to form a ventilated barrier according to my invention. These members are secured together in nested relation preferably along their sides by any convenient means. The means shown, however, comprises insulating rivets 12 which pass through the sides of both members near their upper ends and also through their lower ends but are not shown, as such portions are indicated as broken away.

These members are spaced apart laterally so as to provide a ventilating space between the back portions 14: and 15 of the members 10 and 11 respectively. This arrangement is accomplished by making the upstanding sides of member 10 deeper than the corresponding sides of member 11; the edges of the sides of the two members being made to coincide. The depth of this space is limited by the distance between the edge of the windings to be insulated and the core or other part from which the windings are to be rotected.

his arrangement is clearly shown in Fig. 2 where the three legged core 17 has concentric windings 18 surrounding its central leg 19. The insulating barriers composed of members 10 and 11 are shown as inserted between the edge of the windings and the outer legs of the core which the upstanding sides of the insulating channels partially envelop.

The barriers of my invention are arranged not merely to insulate the sides of windings from the outer core legs but also to insulate the windings from yoke portions of the core as well. Accordingly the spaced insulating members do not terminate with upper and lower ends of the vertical clearance spaces between the windings and legs. Each of members 10 and 11 have bent-over channel portions 20 and 21 respectively, the sides of members 10 and 11 being slit in a direction normal to their backs in order to facilitate bending, as indicated at 22 and 23. The

sides of the outer member 10 are slit however'at two points relatively close together and the intervening piece taken out, thus providing a notch in each side at the place of bending. The outer channel member is indicated as having its portion 20 bent back on a line joining its uppermost slits at the upper end (the line of bending at the lower en joining the lowermost slits), so that the notches in the sides consequently serve as lateral openings as indicated at 25, thereby providing in ess and egress to the space between the c annel members 10 and 11.

The ends of the bent back portions 20 and 21 are cut to have a configuration fitting closely about the central leg 19; such ortions generally not being spaced apart, since as a rule they are not in a strong electrostatic field where dielectric hysteresis must be reckoned with.

Barriers constructed in accordance with my invention permit a continuous ingress of a cooling and insulating medium into the space between the channel member through the lateral openings at the lower end, and egress thereof through the openings at the upper end; thus dissipating the heat by convection which may be en endered in the barrier construction by die ectric hysteresis or other causes acting during the operation of the electrical apparatus.

Having now described an embodiment of my invention which is at present .the best means known to me for carrying the same into effect, I'would have it understood that this is merely illustrative and that I do not mean to be limited thereby to the precise details shown, nor restricted in the choice of recognized equivalents except as defined in my claims hereunto annexed.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. In an electrical apparatus the combination with a winding and a part to be insulated therefrom, of an insulating barrier disposed between said winding and part comprising spaced members rovided with sides partially enveloping sai part and having ateral openings therein to afford circulation of a cooling and ventilating medium.

2. In an electrical apparatus the combination with a winding and a part to be insulated therefrom, of an insulating barrier disposed between said winding and part comprising spaced channel members arranged in nested relation and having their sides Jilltially enveloping said part and provlded with lateral openings to the space therebetween formed by notching the sides of the outer channel member.

3. In an electrical apparatus the combination with a winding and a part to be insulated therefrom, of an insulating barrier disposed between said winding and part c0mprising spaced channel members arranged in nested relation having bent-over end portions and sides arranged to partially envelop said part and provided with openings formed by slitting said sides adjacent the bent-over ortions whereby ingress and egress is a orded for a cooling and ventilating medium to the space between said members.

In witness whereof, I have hereunto set my hand this 13th (I, of Nov., 1920.

WILKIAM O. DWYER. 

